Vehicle-mounted control system for automatically stretching out electric step based on recreational vehicle

Abstract

The invention discloses a vehicle-mounted control system for automatically stretching out an electric step on the basis of a motor home, which comprises a controller matched with an electric step body, a remote controller, a mechanical trigger switch, an external single-pole double-throw control switch, a dual-drive synchronous transmission mechanism, an external illuminating lamp, an extension cable, a safety protection system and a power supply circuit, the controller is in signal or drive connection with the mechanical trigger switch, the external single-pole double-throw control switch, the dual-drive synchronous transmission mechanism, the external illuminating lamp and the safety protection system. By means of a triple control mode, driving mistaken extension is eradicated, full-scene safety protection is constructed through infrared and current dual anti-pinch and starting load bearing detection, a high-adaptability structure and differentiation state prompting are matched, the operation stability and operation convenience are remarkably improved, risks such as pinch injury and overload damage are thoroughly avoided, and the safety performance of a vehicle is improved. And diversified use requirements of the motor home are comprehensively met.

Description

Technical Field

[0001] This invention relates to the field of RV technology, and in particular to an on-board control system based on an RV that automatically extends electric steps. Background Technology

[0002] Electric steps, as an important auxiliary device for RV chassis, lower the entry and exit height through automatic retraction, improving the convenience for users. They are widely used in various RV models. However, existing RV electric step systems still have many technical shortcomings, making it difficult to meet users' comprehensive needs for stability, safety, and convenience.

[0003] Existing electric steps mostly employ a single drive mechanism and simple control logic. For example, some products rely solely on door control triggers for extension and retraction, which can easily lead to false triggering when the vehicle door moves slightly on bumpy roads, causing the steps to extend unintentionally during driving, posing a significant safety hazard. Furthermore, in terms of safety protection, existing technologies generally suffer from limited protection: some products only have basic anti-pinch functions, relying on a single pressure sensor to detect obstacles, resulting in low detection accuracy and susceptibility to environmental interference; most products lack a load-bearing detection unit, meaning that when the steps are not fully extended or the load exceeds the limit, uneven force can easily damage the transmission mechanism, even causing falls. In addition, existing electric steps have relatively simple control methods, lacking flexible manual intervention and remote control capabilities. In emergency situations (such as door switch malfunctions), they cannot quickly control the extension and retraction of the steps, resulting in poor usability. In light of the above, this application proposes an onboard control system for automatically extending electric steps in RVs. Summary of the Invention

[0004] Based on the technical problems existing in the background technology, the present invention proposes an on-board control system based on the automatic extension of electric steps in a motorhome.

[0005] The present invention proposes an on-board control system for an RV with an automatically extending electric step, comprising a controller that works with the electric step body, a remote control, a mechanical trigger switch, an external single-pole double-throw control switch, a dual-drive synchronous transmission mechanism, an external lighting lamp, an extension cable, a safety protection system, and a power supply circuit. The controller establishes signal or drive connections with the mechanical trigger switch, the external single-pole double-throw control switch, the dual-drive synchronous transmission mechanism, the external lighting lamp, and the safety protection system, respectively.

[0006] The extension cable is used to extend the connection distance between components;

[0007] The dual-drive synchronous transmission mechanism includes an action mechanism, a drive motor, a synchronous transmission component, and two drive shafts. The action mechanism is a double-layer pedal structure, and an external lighting lamp is installed on the lower side of the double-layer pedal structure. The external lighting lamp is used to provide illumination after the electric step body is extended.

[0008] The controller has a built-in main control board, which includes a main control chip, a crystal oscillator chip, a ULN2003 chip, a buzzer alarm circuit, a voltage acquisition circuit, a current acquisition circuit, and relay and MOSFET drive circuits. The crystal oscillator chip provides a 12M clock signal to the main control chip, the ULN2003 chip provides driving force for the control of the relay and MOSFET drive circuits, the buzzer alarm circuit is used to issue an audible prompt when the electric step body is fully opened or fully retracted, and the voltage acquisition circuit and current acquisition circuit are used to acquire the voltage of the power supply circuit and the current of the drive motor, respectively.

[0009] The safety protection system includes an anti-pinch and anti-collision protection unit and a load-bearing detection unit;

[0010] The power supply circuit includes a power supply and a step-down circuit. The power supply is a vehicle-mounted 12V battery, and the step-down circuit is used to convert the 12V input voltage to 5V to provide operating voltage for each functional module.

[0011] Preferably, the controller includes a housing with a cable outlet at the bottom. A cable approximately 30cm in length is led out from the cable outlet, and a waterproof connector is fitted at the base of the cable. The waterproof connector is used to adapt and connect with the connector of the cable leading out of the electric step body or the connector of the extension cable. The controller housing is made of ABS engineering plastic with an IP67 protection rating. The cable outlet is sealed with a silicone sealing ring. The temperature resistance range of the cable is -40℃ to 85℃.

[0012] Preferably, the remote control is provided with six function buttons, namely, wake-up button, pairing button, extend button, retract button, lock button and unlock button;

[0013] The wake-up button is used to wake the remote control from sleep mode;

[0014] The pairing key is used to establish a communication connection between the remote control and the controller;

[0015] The extend key is used to output a command to control the extension of the electric step body;

[0016] The retraction key is used to output a command to control the retraction of the electric step body;

[0017] The locking key is used to lock the remote control; pressing it will stop the response of the door control and manual switch.

[0018] The unlock button is used to release the remote control; pressing it will restart the door control and manual switch.

[0019] The remote control has a built-in control board. The controller's main control board and the remote control board establish a wireless communication link through the WL500B RF chip. The effective communication distance of the wireless communication link is about 8 meters. The remote control board needs to complete pairing and authentication with the controller's main control board before it can transmit control commands.

[0020] Preferably, the vehicle control system adopts a triple control method, including a low-priority gate triggering method, a high-priority manual triggering method, and a remote control triggering method that can acquire control.

[0021] The door control triggering method collects the door opening and closing signals through a mechanical trigger switch installed on the vehicle door. The door opening and closing signals are used as trigger commands. When the door opening angle is ≥30°, an extension signal is triggered to control the extension of the electric step body. When the door closing angle is ≤5°, a retraction signal is triggered to control the retraction of the electric step body. The door control triggering also has a 1-second delay function to prevent false triggering caused by slight movement of the door on bumpy roads.

[0022] The manual triggering method directly inputs control commands through an external single-pole double-throw control switch. The control commands are independent of the door opening and closing signals and are used to control the extension or retraction of the electric step body.

[0023] The remote control is triggered by pressing the extend or retract button after gaining control. This will not trigger the safety protection system and can be used in emergency situations.

[0024] The priority order of the three control modes is: remote control > manual trigger > door trigger; when different control modes conflict, the higher priority control mode immediately interrupts the lower priority control action and executes its own command.

[0025] When any control mode is triggered, the drive motor moves to drive the double-layer pedal structure to perform telescopic movement. When the pedal is fully extended or fully retracted to the preset limit position, the system triggers the buzzer to issue a prompt signal.

[0026] Preferably, the buzzer alarm circuit emits three beeps at a frequency of 1kHz when the electric step body is fully opened or fully retracted, each beep lasting 0.2s with an interval of 0.1s; when the electric step body is overloaded or encounters an obstacle, the buzzer continues to sound until the abnormal state is resolved.

[0027] Preferably, the buzzer alarm circuit includes a buzzer, an NPN transistor Q1, a current-limiting resistor R1, a filter capacitor C1, and a freewheeling diode D1. The buzzer is connected to the main control chip of the controller's main control board through the NPN transistor Q1. The main control chip outputs a pulse signal or a continuous signal to control the buzzer to emit differentiated prompt sounds. The filter capacitor C1 is used to filter out power supply fluctuations, and the freewheeling diode D1 prevents the transistor from being damaged by the reverse electromotive force.

[0028] The voltage acquisition circuit includes a voltage divider resistor R2, an operational amplifier U1, a filter capacitor C2, and a first A / D conversion module integrated into the main control chip. The voltage divider resistor R2 reduces the voltage of the vehicle's 12V battery to about 3.7V. After being amplified by the operational amplifier U1 and filtered by the filter capacitor C2, the voltage is input to the first A / D conversion module to be converted into a digital signal, thereby realizing battery voltage monitoring.

[0029] The current acquisition circuit includes a sampling resistor R3, an operational amplifier U2, a filter capacitor C2, and a second A / D conversion module. The sampling resistor R3 is connected in series in the power supply circuit of the drive motor to acquire the weak voltage signal generated by the motor current. After being amplified by 20 times by the operational amplifier U2, it is input into the A / D conversion module to calculate the actual motor current, which is used for overload and obstacle detection.

[0030] The relay and MOSFET driving circuit includes a relay, a MOSFET, a driving chip, a freewheeling diode D2, and a protection resistor R3. The driving chip amplifies the control signal from the main control chip, drives the relay to switch the motor power supply circuit on and off, and the MOSFET controls the forward and reverse rotation of the motor. The freewheeling diode D2 absorbs the reverse electromotive force of the motor, and the protection resistor R3 provides overcurrent and overheat protection.

[0031] Preferably, the anti-pinch and anti-collision protection unit achieves dual obstacle detection through infrared sensor and motor current threshold detection. When an obstacle is detected, the electric step stops moving within 0.1s, retracts 5cm in the opposite direction after a 2s delay, and the pinching force is ≤50N.

[0032] The specific operating steps are as follows:

[0033] S101: When the electric stepper body receives the extension / retraction command and the drive motor starts, the anti-pinch and anti-collision protection unit simultaneously completes parameter initialization. When configuring the infrared sensor parameters, the infrared emitting / receiving tube with a wavelength of 940nm is activated, the scanning frequency is set to 100Hz, the detection range covers the 0-30cm area of ​​the stepper extension path, and the preset "no obstacle" light intensity threshold is set - when the light intensity is <500lux, it is judged as an obstruction. At the same time, the current acquisition circuit is activated, the sampling frequency is set to 200Hz, and the "stop response delay ≤0.1s", "reverse retraction delay = 2s", and "reverse retraction distance S = 5cm" are set. At the same time, the fixed parameters of the retraction distance calculation formula are loaded.

[0034] S102: During the extension and retraction of the electric stepper body, the infrared sensor and current detection work synchronously. When there is no obstacle, the infrared light is unobstructed, the light intensity of the receiver tube is ≥500 lux, and a "no obstacle" signal is output. When there is an obstacle, the infrared light is blocked, the light intensity of the receiver tube is <500 lux, and a "obstacle present" signal is output. The blocking time is recorded. Meanwhile, the current acquisition circuit collects the motor current through sampling resistor R3, and after amplification and filtering, calculates the real-time current value using the second A / D conversion formula. : Where D is the A / D quantization value, and for five consecutive acquisitions By averaging the values ​​and eliminating instantaneous fluctuations, a smoothed current is obtained. : It also calculates the difference between the current smoothing current and the static current to determine whether it is close to the stagnation threshold. ;

[0035] S103: The controller performs an OR logic judgment on the dual detection results. If the infrared sensor outputs an "obstacle present" signal three times consecutively, and strong light interference is excluded, it is judged as an "infrared anomaly." ≥15A, and duration ≥ Simultaneously, the clamping force is verified to be ≤50N using the clamping force formula, which determines it as "abnormal current". The clamping force formula is as follows: If either "infrared anomaly" or "current anomaly" is detected, "obstacle present" is marked, triggering an action response; if both detections are normal, the stepping motion continues.

[0036] S104: After determining that "there is an obstacle", the controller executes actions in three levels within 0.1 seconds:

[0037] Level 1: The controller immediately outputs a stop command, the relay disconnects the motor power supply, the MOSFET is cut off, the drive motor stops rotating within 0.1 seconds, and the pedal stops moving;

[0038] Level 2: Start the "reverse retraction timer", keep the machine stopped for 2 seconds, and the buzzer will sound continuously. During the timer, monitor the dual signals: if the obstacle is removed, cancel the subsequent retraction action; if it is still abnormal, proceed to the next step.

[0039] Level 3: Calculate the motor reversal time t using the "retraction distance formula" to ensure a precise retraction of 5cm. The formula used is: ;

[0040] S105: When the pedal retracts 5cm in the opposite direction, or when the obstacle is removed, the anti-pinch and anti-collision protection unit resets.

[0041] Preferably, the load-bearing detection unit detects the load-bearing status of the electric step body when it starts through the motor current detection circuit. The detection time window is within 0.5 seconds after startup. When the starting current of the drive motor exceeds 8A, it is determined that the load exceeds the allowable range, and the electric step body is controlled to stop immediately while triggering a buzzer alarm.

[0042] Its specific operational logic steps are as follows:

[0043] S201: When the user triggers the electric step extension command and the controller receives the "extension ready" signal, the load-bearing detection unit synchronously completes initialization;

[0044] S202: When the controller outputs a "motor start command" and the drive motor starts to rotate, the load detection unit immediately enters the "start current detection mode" to continuously collect and process current data. The controller starts the "detection time window timer" to record the motor start time. Ensure that only t∈[ , The current is detected within +0.5s, and automatically exits the load detection mode after 0.5s. The current acquisition circuit acquires the starting current signal in real time through the sampling resistor connected in series in the motor power supply circuit. After amplification and A / D conversion, the real-time motor starting current is calculated using the following formula: Where D is the digital quantization value output by the A / D converter. This is the A / D reference voltage. For A / D resolution, This refers to the operational amplifier's gain. The sampling resistor value was used to collect 100 sets of data within 0.5 seconds. The value is subjected to "peak filtering"—outlier values ​​that are transient disturbances are removed, and the maximum current value is retained. ;

[0045] S203: When the detection time window ends or a significantly over-threshold current is detected before the end of the detection time window, the controller uses a dual logic of "current threshold judgment + weight formula verification" to determine whether the load exceeds the allowable range: comparing the maximum starting current selected from the data. Overload detection threshold =8A, if ≤8A: Determined as "normal load-bearing capacity", the load-bearing detection unit exits, and the electric stepper continues to extend. >8A: Proceed to the second step, "Weight Formula Verification," to confirm whether it is a genuine overload and calculate the actual load weight G corresponding to the current maximum starting current. Verify whether it exceeds the allowable upper limit of 200kg. The calculation formula is as follows: ;

[0046] S204: If If the current exceeds 8A and the calculated G is greater than 200kg, it is judged as "load exceeds the allowable range"; if only the current exceeds the threshold but the calculated G is less than or equal to 200kg, it is judged as "current fluctuation", the test result is ignored, and the extension action continues.

[0047] S205: When the load is determined to be "exceeding the allowable range", the controller will simultaneously execute two operations within 0.1s: immediately stop the electric stepper and sound a buzzer alarm. During the overload alarm, the system locks all extension commands. The lock can only be released after the load is removed by "manually pressing the retraction button" or "unlocking with the remote control" to prevent overload restart.

[0048] Preferably, the MOS transistor drive circuit of the controller main control board is connected to the drive motor to control the forward and reverse rotation of the drive motor, thereby realizing the extension and retraction of the electric step.

[0049] Compared with existing technologies, the beneficial effects of this invention are:

[0050] 1. In addition to door control triggering, manual triggering and remote control triggering are added, with priority response in the order of "remote control > manual > door control". Door control triggering has a 1-second delay - even if the door moves slightly on a bumpy road, the pedal will not be triggered to extend, completely eliminating the safety hazard of pedal misoperation while driving. Furthermore, a dual-drive synchronous transmission mechanism is used instead of a single drive to avoid false triggering caused by drive mechanism failure.

[0051] 2. The system adopts a dual mechanism of "infrared sensor + motor current detection" - the infrared sensor scans at a high frequency of 100Hz, and determines occlusion when the light intensity is <500 lux; the motor current detection samples at 200Hz, and determines lag when ΔI≥15A and lasts for 50ms. The dual "OR logic" ensures no missed detections, effectively improving detection accuracy.

[0052] 3. Regarding the issue of "pedal not deploying / overload causing damage or personnel falling," monitor the starting current within 0.5 seconds after the motor starts. When the load exceeds 8A, the machine will immediately stop and alarm, and the extension command will be locked at the same time. This fills the gap in the existing technology of no load-bearing detection, avoids deformation of the transmission mechanism due to overload, and reduces the probability of personnel falling accidents.

[0053] 4. Through three control methods, the remote control supports 8-meter wireless operation, which is compatible with the user's external extension / retraction of the pedals; the manual switch is installed next to the driver's seat / door, which is compatible with emergency intervention in case of door control failure; and the door control linkage realizes automatic operation without manual triggering - the three methods respond according to priority, covering all usage scenarios such as RV parking, driving, and maintenance.

[0054] This invention prevents accidental extension during driving through a triple control method. It constructs a full-scenario safety protection system with dual anti-pinch technology ("infrared + current") and starting load detection. Combined with a highly adaptable structure and differentiated status prompts, it not only significantly improves operational stability and ease of operation, but also completely avoids risks such as pinching and overload damage, fully meeting the diverse usage needs of RVs. Attached Figure Description

[0055] Figure 1 This is a block diagram of an onboard control system for an RV that automatically extends electric steps, as proposed in this invention.

[0056] Figure 2 This is a flowchart of an onboard control system for an RV that automatically extends electric steps, as proposed in this invention. Detailed Implementation

[0057] The present invention will be further explained below with reference to specific embodiments.

[0058] Example

[0059] Reference Figure 1-2 This embodiment proposes an on-board control system for an RV with an automatically extended electric step, including a controller, a remote control, a mechanical trigger switch, an external single-pole double-throw control switch, a dual-drive synchronous transmission mechanism, an external lighting lamp, an extension cable, a safety protection system, and a power supply circuit that cooperate with the electric step body. The controller establishes signal or drive connections with the mechanical trigger switch, the external single-pole double-throw control switch, the dual-drive synchronous transmission mechanism, the external lighting lamp, and the safety protection system, respectively.

[0060] Extension cables are used to extend the connection distance between components;

[0061] The dual-drive synchronous transmission mechanism includes an action mechanism, a drive motor, a synchronous transmission component, and two drive shafts. The action mechanism is a double-layer pedal structure. An external light is installed on the lower side of the double-layer pedal structure. The external light is used to provide illumination after the electric step body is extended.

[0062] The drive motor is a 12V DC drive motor with a rated power of 50W and a speed of 300rpm, fixed to the transmission housing. The synchronous transmission assembly includes a drive gear and a driven gear, which mesh with each other. The output shaft of the drive motor is fixedly connected to the drive gear, and dual-drive linkage is achieved through gear meshing to ensure that the left and right drive shafts rotate at the same speed. The two drive shafts are respectively adapted to the keyways of the driven gear and the side end connecting seats of the double-layer pedal structure. The double-layer pedal structure includes an upper main load-bearing aviation aluminum alloy pedal, a lower auxiliary support pedal, and a support column connecting the upper main load-bearing aviation aluminum alloy pedal and the lower auxiliary support pedal. The pedal extension range is 15cm above the ground after extension and ≤3cm between the pedal and the chassis after retraction. The external lighting is an LED light source with a power of 3W, a color temperature of 6000K, and an illumination range of ≥0.5m×1.2m. It turns on when the pedal extension reaches 50% of the total stroke and turns off when the pedal retraction reaches 50% of the total stroke.

[0063] The controller has a built-in main control board, which includes a main control chip, a crystal oscillator chip, a ULN2003 chip, a buzzer alarm circuit, a voltage acquisition circuit, a current acquisition circuit, and relay and MOSFET drive circuits. The crystal oscillator chip provides a 12MHz clock signal to the main control chip, the ULN2003 chip provides driving force for the relay and MOSFET drive circuits, the buzzer alarm circuit is used to issue an audible prompt when the electric step body is fully open or fully retracted, and the voltage acquisition circuit and current acquisition circuit are used to acquire the voltage of the power supply circuit and the current of the drive motor, respectively.

[0064] The MOS transistor drive circuit of the controller's main control board is connected to the drive motor to control the forward and reverse rotation of the drive motor, thereby realizing the extension and retraction of the electric step.

[0065] The buzzer alarm circuit emits three beeps at a frequency of 1kHz when the electric step body is fully opened or fully retracted, each beep lasting 0.2s with an interval of 0.1s; when the electric step body is overloaded or encounters an obstacle, the buzzer will continue to sound until the abnormal state is resolved.

[0066] The buzzer alarm circuit includes a buzzer, an NPN transistor Q1, a current-limiting resistor R1, a filter capacitor C1, and a freewheeling diode D1. The buzzer is connected to the main control chip of the controller's main control board through the NPN transistor Q1. The main control chip outputs a pulse signal or a continuous signal to control the buzzer to emit differentiated prompt sounds. The filter capacitor C1 is used to filter out power supply fluctuations, and the freewheeling diode D1 prevents the transistor from being damaged by the reverse electromotive force.

[0067] The voltage acquisition circuit includes a voltage divider resistor R2, an operational amplifier U1, a filter capacitor C2, and a first A / D conversion module integrated into the main control chip. The voltage divider resistor R2 reduces the voltage of the vehicle's 12V battery to about 3.7V. After being amplified by the operational amplifier U1 and filtered by the filter capacitor C2, the voltage is input to the first A / D conversion module to be converted into a digital signal, thereby realizing battery voltage monitoring.

[0068] The current acquisition circuit includes a sampling resistor R3, an operational amplifier U2, a filter capacitor C2, and a second A / D conversion module. The sampling resistor R3 is connected in series in the power supply circuit of the drive motor to acquire the weak voltage signal generated by the motor current. After being amplified by 20 times by the operational amplifier U2, it is input into the A / D conversion module to calculate the actual motor current, which is used for overload and obstacle detection.

[0069] The relay and MOSFET drive circuit includes a relay, a MOSFET, a driver chip, a freewheeling diode D2, and a protection resistor R3. The driver chip amplifies the control signal from the main control chip, drives the relay to switch the motor power supply circuit on and off, the MOSFET controls the forward and reverse rotation of the motor, the freewheeling diode D2 absorbs the reverse electromotive force of the motor, and the protection resistor R3 provides overcurrent and overheat protection.

[0070] The controller includes a housing with a cable outlet at the bottom. A cable approximately 30cm long extends from the cable outlet, and a waterproof connector is fitted at the base of the cable. The waterproof connector is used to connect with the connector of the cable leading out of the electric step body or the connector of the extension cable. The controller housing is made of ABS engineering plastic with an IP67 protection rating. The cable outlet is sealed with a silicone sealing ring. The cable has a temperature resistance range of -40℃ to 85℃.

[0071] The remote control has six function buttons: wake-up button, pairing button, extend button, retract button, lock button, and unlock button.

[0072] The wake-up button is used to wake the remote control from sleep mode;

[0073] The pairing button is used to establish a communication connection between the remote control and the controller;

[0074] The extend button is used to output commands to control the extension of the electric step body;

[0075] The retraction key is used to output a command to control the retraction of the electric step body;

[0076] The lock button is used to lock remote control operation; pressing it will stop the door control and manual switch response.

[0077] The unlock button is used to release remote control control; pressing it will restore the door control and manual switch functionality.

[0078] The remote control has a built-in control board. The controller's main control board and the remote control board establish a wireless communication link through the WL500B RF chip. The effective communication distance of the wireless communication link is about 8 meters. The remote control board needs to be paired and authenticated with the controller's main control board before it can transmit control commands.

[0079] The safety protection system includes an anti-pinch and anti-collision protection unit and a load-bearing detection unit;

[0080] The anti-pinch and anti-collision protection unit achieves dual obstacle detection through infrared sensors and motor current threshold detection. When an obstacle is detected, the electric step stops moving within 0.1s, and retracts 5cm in the opposite direction after a 2s delay, with the pinching force ≤50N.

[0081] The specific operating steps are as follows:

[0082] S101: When the electric stepper body receives the extension / retraction command and the drive motor starts, the anti-pinch and anti-collision protection unit simultaneously completes parameter initialization. When configuring the infrared sensor parameters, the infrared emitting / receiving tube with a wavelength of 940nm is activated, the scanning frequency is set to 100Hz, the detection range covers the 0-30cm area of ​​the stepper extension path, and the preset "no obstacle" light intensity threshold is set - when the light intensity is <500lux, it is judged as an obstruction. At the same time, the current acquisition circuit is activated, the sampling frequency is set to 200Hz, and the "stop response delay ≤0.1s", "reverse retraction delay = 2s", and "reverse retraction distance S = 5cm" are set. At the same time, the fixed parameters of the retraction distance calculation formula are loaded.

[0083] S102: During the extension and retraction of the electric stepper body, the infrared sensor and current detection work synchronously. When there is no obstacle, the infrared light is unobstructed, the light intensity of the receiver tube is ≥500 lux, and a "no obstacle" signal is output. When there is an obstacle, the infrared light is blocked, the light intensity of the receiver tube is <500 lux, and a "obstacle present" signal is output. The obstruction time t1 is recorded. At the same time, the current acquisition circuit collects the motor current through the sampling resistor R3. After amplification and filtering, the real-time current value is calculated by the second A / D conversion formula. : Where D is the A / D quantization value, and for five consecutive acquisitions By averaging the values ​​and eliminating instantaneous fluctuations, a smoothed current is obtained. : It also calculates the difference between the current smoothing current and the static current to determine whether it is close to the stagnation threshold. ;

[0084] S103: The controller performs an OR logic judgment on the dual detection results. If the infrared sensor outputs an "obstacle present" signal three times consecutively, and strong light interference is excluded, it is judged as an "infrared anomaly." ≥15A, and duration ≥ Simultaneously, the clamping force is verified to be ≤50N using the clamping force formula, which determines it as "abnormal current". The clamping force formula is as follows: If either "infrared anomaly" or "current anomaly" is detected, "obstacle present" is marked, triggering an action response; if both detections are normal, the stepping motion continues.

[0085] S104: After determining that "there is an obstacle", the controller executes actions in three levels within 0.1 seconds:

[0086] Level 1: The controller immediately outputs a stop command, the relay disconnects the motor power supply, the MOSFET is cut off, the drive motor stops rotating within 0.1 seconds, and the pedal stops moving;

[0087] Level 2: Start the "reverse retraction timer", keep the machine stopped for 2 seconds, and the buzzer will sound continuously. During the timer, monitor the dual signals: if the obstacle is removed, cancel the subsequent retraction action; if it is still abnormal, proceed to the next step.

[0088] Level 3: Calculate the motor reversal time t using the "retraction distance formula" to ensure a precise retraction of 5cm. The formula used is: ;

[0089] S105: When the pedal retracts 5cm in the opposite direction, or when the obstacle is removed, the anti-pinch and anti-collision protection unit resets.

[0090] The load-bearing detection unit detects the load status of the electric step body when it starts through the motor current detection circuit. The detection time window is within 0.5 seconds after startup. When the starting current of the drive motor exceeds 8A, it is determined that the load exceeds the allowable range, and the electric step body is controlled to stop immediately and the buzzer alarm is triggered.

[0091] Its specific operational logic steps are as follows:

[0092] S201: When the user triggers the electric step extension command and the controller receives the "extension ready" signal, the load-bearing detection unit synchronously completes initialization;

[0093] S202: When the controller outputs a "motor start command" and the drive motor starts to rotate, the load detection unit immediately enters the "start current detection mode" to continuously collect and process current data. The controller starts the "detection time window timer" to record the motor start time. Ensure that only t∈[ , The current is detected within +0.5s, and automatically exits the load detection mode after 0.5s. The current acquisition circuit acquires the starting current signal in real time through the sampling resistor connected in series in the motor power supply circuit. After amplification and A / D conversion, the real-time motor starting current is calculated using the following formula: Where D is the digital quantization value output by the A / D converter. This is the A / D reference voltage. For A / D resolution, This refers to the operational amplifier's gain. The sampling resistor value was used to collect 100 sets of data within 0.5 seconds. The value is subjected to "peak filtering"—outlier values ​​that are transient disturbances are removed, and the maximum current value is retained. ;

[0094] S203: When the detection time window ends or a significantly over-threshold current is detected before the end of the detection time window, the controller uses a dual logic of "current threshold judgment + weight formula verification" to determine whether the load exceeds the allowable range: comparing the maximum starting current selected from the data. Overload detection threshold =8A, if ≤8A: Determined as "normal load-bearing capacity", the load-bearing detection unit exits, and the electric stepper continues to extend. >8A: Proceed to the second step, "Weight Formula Verification," to confirm whether it is a genuine overload and calculate the actual load weight G corresponding to the current maximum starting current. Verify whether it exceeds the allowable upper limit of 200kg. The calculation formula is as follows: ;

[0095] S204: If If the current exceeds 8A and the calculated G is greater than 200kg, it is judged as "load exceeds the allowable range"; if only the current exceeds the threshold but the calculated G is less than or equal to 200kg, it is judged as "current fluctuation", the test result is ignored, and the extension action continues.

[0096] S205: When the load is determined to be "exceeding the allowable range", the controller will simultaneously execute two operations within 0.1s: immediately stop the electric stepper and sound a buzzer alarm. During the overload alarm, the system locks all extension commands. The lock can only be released after the load is removed by "manually pressing the retraction button" or "unlocking with the remote control" to prevent overload restart.

[0097] The power supply circuit includes a power supply and a step-down circuit. The power supply is a 12V vehicle battery, and the step-down circuit is used to convert the 12V input voltage to 5V to provide the operating voltage for each functional module.

[0098] The vehicle control system adopts a triple control method, including a low-priority gate triggering method, a high-priority manual triggering method, and a remote control triggering method that can acquire control.

[0099] The door control triggering method collects the door opening and closing signals through a mechanical trigger switch installed on the vehicle door. The door opening and closing signals are used as trigger commands. When the door opening angle is ≥30°, an extension signal is triggered to control the extension of the electric step body. When the door closing angle is ≤5°, a retraction signal is triggered to control the retraction of the electric step body. The door control triggering also has a 1-second delay function to prevent false triggering caused by slight movement of the door on bumpy roads.

[0100] The manual triggering method directly inputs control commands through an external single-pole double-throw control switch. The control commands are independent of the door opening and closing signals and are used to control the extension or retraction of the electric step body.

[0101] The remote control is triggered by pressing the extend or retract button after gaining control. This will not trigger the safety protection system and can be used in emergency situations.

[0102] The priority order of the three control modes is: remote control > manual trigger > door trigger; when different control modes conflict, the higher priority control mode immediately interrupts the lower priority control action and executes its own command.

[0103] When any control mode is triggered, the drive motor moves to drive the double-layer pedal structure to perform telescopic movement. When the pedal is fully extended or fully retracted to the preset limit position, the system triggers the buzzer to issue a prompt signal.

[0104] This embodiment uses a triple control method to prevent accidental extension while driving. It constructs a full-scenario safety protection system with dual anti-pinch technology ("infrared + current") and starting load detection. Combined with a highly adaptable structure and differentiated status prompts, it not only significantly improves operational stability and ease of operation, but also completely avoids risks such as pinching and overload damage, fully meeting the diverse usage needs of RVs.

[0105] In this embodiment, a 12V vehicle battery is used as the power supply. The current first enters the step-down module of the power supply circuit, which stably converts the 12V input voltage to a 5V output, supplying power to the main control chip of the controller main control board, the buzzer alarm circuit, the voltage acquisition circuit, the current acquisition circuit, and other low-voltage functional modules. At the same time, the 12V battery directly supplies power to high-voltage actuators such as the drive motor and relays. After the power supply is completed, the controller main control board automatically initializes, the crystal oscillator chip provides a 12M clock signal to the main control chip, the ULN2003 chip enters standby mode to prepare to drive the relays and MOSFETs, the voltage acquisition circuit starts monitoring the battery voltage, the current acquisition circuit initializes the sampling parameters, the safety protection system loads the preset threshold, and the infrared sensor starts and enters the scanning mode.

[0106] When the user activates the device via the remote control's wake-up button, pressing the pairing button completes pairing authentication between the remote control board and the controller's main control board via the WL500B RF chip. Pressing the extend / retract button sends a wireless command to the controller. The main control chip receives the command, amplifies the signal via the ULN2003 chip, drives the relay to connect the motor power supply circuit, and controls the motor's forward and reverse rotation via a MOSFET. Pressing the lock button stops the system from responding to door control and manual switch signals, retaining only remote control control privileges. Pressing the unlock button restores all control modes. During manual triggering, the user operates the external single-pole double-throw control switch, which directly outputs an independent control command to the controller. If door control is in progress at this time, the controller immediately interrupts the low-priority door control action and prioritizes the manual command, driving the motor via the relay and MOSFET. During door control triggering, a mechanical trigger switch installed at the door hinge collects door opening and closing signals: when the door opening angle is ≥30°, the switch outputs an extend signal; when the door closing angle is ≤5°, it outputs a retract signal. After processing by the controller, the signal triggers the door control logic, driving the motor to extend and retract the pedal.

[0107] The drive signal output by the controller is amplified by the ULN2003 chip, and the relay connects the power supply circuit of the drive motor. The MOS controls the forward and reverse rotation of the drive motor. The power of the drive motor is transmitted to the two drive shafts through the synchronous transmission component. The drive shafts are rigidly connected to the double-layer pedal structure through the side end connecting seat, converting the rotational power into the linear extension and retraction motion of the pedal. When the double-layer pedal extends to 50% of the total stroke, the controller automatically triggers the external lighting to turn on; when the pedal retracts to 50% of the total stroke, the lighting turns off synchronously, without manual operation.

[0108] Meanwhile, the infrared sensor continuously scans the pedal extension path. If an obstacle is detected, the controller outputs an "obstacle detected" signal three times consecutively, and then determines that the infrared sensor is faulty. At the same time, the current acquisition circuit collects the motor current in real time, amplifies and filters it, and then calculates a smooth current value. ,like Difference from quiescent current If the current is ≥15A and lasts for 50ms, it is determined to be "abnormal current". After any abnormality is triggered, the controller cuts off the power supply to the motor within 0.1s to stop the pedal. After a 2s delay, the motor is driven to reverse and the pedal is retracted 5cm in the opposite direction. At the same time, the buzzer continues to sound an alarm.

[0109] Furthermore, within 0.5 seconds after the drive motor starts, the current acquisition circuit continuously collects the starting current, discards abnormal values, and retains the maximum starting current. ,like >8A, through the formula Verify the load capacity. If G > 200kg, it is considered overloaded. The controller immediately cuts off the motor power supply, the pedal stops moving, the buzzer sounds a continuous alarm, and all extension commands are locked. The lock can only be released manually or by remote control after the load is removed. When the pedal is fully extended or retracted to the preset limit position, the controller triggers the buzzer alarm circuit to emit three beeps to inform the user that the action is complete. The voltage acquisition circuit synchronously feeds back the battery voltage. After the action is completed, the controller turns off the drive motor and lights, the safety protection system clears historical detection data, the current / voltage acquisition circuit returns to standby sampling state, and the entire system waits for the next control command.

[0110] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A vehicle-mounted control system based on an automatically extending electric step in a motorhome, characterized in that, The device includes a controller, remote control, mechanical trigger switch, external single-pole double-throw control switch, dual-drive synchronous transmission mechanism, external lighting, extension cable, safety protection system and power supply circuit that work with the electric step body. The controller establishes signal or drive connections with the mechanical trigger switch, external single-pole double-throw control switch, dual-drive synchronous transmission mechanism, external lighting and safety protection system respectively. The extension cable is used to extend the connection distance between components; The dual-drive synchronous transmission mechanism includes an action mechanism, a drive motor, a synchronous transmission component, and two drive shafts. The action mechanism is a double-layer pedal structure, and an external lighting lamp is installed on the lower side of the double-layer pedal structure. The external lighting lamp is used to provide illumination after the electric step body is extended. The controller has a built-in main control board, which includes a main control chip, a crystal oscillator chip, a ULN2003 chip, a buzzer alarm circuit, a voltage acquisition circuit, a current acquisition circuit, and relay and MOSFET drive circuits. The crystal oscillator chip provides a 12M clock signal to the main control chip, the ULN2003 chip provides driving force for the control of the relay and MOSFET drive circuits, the buzzer alarm circuit is used to issue an audible prompt when the electric step body is fully opened or fully retracted, and the voltage acquisition circuit and current acquisition circuit are used to acquire the voltage of the power supply circuit and the current of the drive motor, respectively. The safety protection system includes an anti-pinch and anti-collision protection unit and a load-bearing detection unit; The power supply circuit includes a power supply and a step-down circuit. The power supply is a vehicle-mounted 12V battery, and the step-down circuit is used to convert the 12V input voltage to 5V to provide operating voltage for each functional module.

2. The vehicle-mounted control system based on the automatic extension of electric steps in a motorhome according to claim 1, characterized in that, The controller includes a housing with a cable outlet at the bottom. A cable approximately 30cm long extends from the cable outlet, and a waterproof connector is fitted at the base of the cable. The waterproof connector is used to connect with the connector of the cable leading out of the electric step body or the connector of the extension cable. The controller housing is made of ABS engineering plastic with an IP67 protection rating. The cable outlet is sealed with a silicone sealing ring. The cable has a temperature resistance range of -40℃ to 85℃.

3. The vehicle-mounted control system based on the automatic extension of electric steps in a motorhome according to claim 1, characterized in that, The remote control has six function buttons: wake-up button, pairing button, extend button, retract button, lock button, and unlock button. The wake-up button is used to wake the remote control from sleep mode; The pairing key is used to establish a communication connection between the remote control and the controller; The extend key is used to output a command to control the extension of the electric step body; The retraction key is used to output a command to control the retraction of the electric step body; The locking key is used to lock the remote control; pressing it will stop the response of the door control and manual switch. The unlock button is used to release the remote control; pressing it will restart the door control and manual switch. The remote control has a built-in control board. The controller's main control board and the remote control board establish a wireless communication link through the WL500B RF chip. The effective communication distance of the wireless communication link is about 8 meters. The remote control board needs to complete pairing and authentication with the controller's main control board before it can transmit control commands.

4. The vehicle-mounted control system based on the automatic extension of electric steps in a motorhome according to claim 1, characterized in that, The vehicle control system adopts a triple control method, including a low-priority gate triggering method, a high-priority manual triggering method, and a remote control triggering method that can acquire control. The door control triggering method collects the door opening and closing signals through a mechanical trigger switch installed on the vehicle door. The door opening and closing signals are used as trigger commands. When the door opening angle is ≥30°, an extension signal is triggered to control the extension of the electric step body. When the door closing angle is ≤5°, a retraction signal is triggered to control the retraction of the electric step body. The door control triggering also has a 1-second delay function to prevent false triggering caused by slight movement of the door on bumpy roads. The manual triggering method directly inputs control commands through an external single-pole double-throw control switch. The control commands are independent of the door opening and closing signals and are used to control the extension or retraction of the electric step body. The remote control is triggered by pressing the extend or retract button after gaining control. This will not trigger the safety protection system and can be used in emergency situations. The priority order of the three control modes is: remote control > manual trigger > door trigger; when different control modes conflict, the higher priority control mode immediately interrupts the lower priority control action and executes its own command. When any control mode is triggered, the drive motor moves to drive the double-layer pedal structure to perform telescopic movement. When the pedal is fully extended or fully retracted to the preset limit position, the system triggers the buzzer to issue a prompt signal.

5. A vehicle-mounted control system based on an automatically extending electric step in a motorhome, as described in claim 1, is characterized in that, The buzzer alarm circuit emits three beeps at a frequency of 1kHz when the electric step body is fully opened or fully retracted, each beep lasting 0.2s with an interval of 0.1s; when the electric step body is overloaded or encounters an obstacle, the buzzer continues to sound until the abnormal state is resolved.

6. A vehicle-mounted control system based on an automatically extending electric step in a motorhome, as described in claim 1, is characterized in that, The buzzer alarm circuit includes a buzzer, an NPN transistor Q1, a current-limiting resistor R1, a filter capacitor C1, and a freewheeling diode D1. The buzzer is connected to the main control chip of the controller's main control board through the NPN transistor Q1. The main control chip outputs a pulse signal or a continuous signal to control the buzzer to emit differentiated prompt sounds. The filter capacitor C1 is used to filter out power supply fluctuations, and the freewheeling diode D1 prevents the transistor from being damaged by the reverse electromotive force. The voltage acquisition circuit includes a voltage divider resistor R2, an operational amplifier U1, a filter capacitor C2, and a first A / D conversion module integrated into the main control chip. The voltage divider resistor R2 reduces the voltage of the vehicle's 12V battery to about 3.7V. After being amplified by the operational amplifier U1 and filtered by the filter capacitor C2, the voltage is input to the first A / D conversion module to be converted into a digital signal, thereby realizing battery voltage monitoring. The current acquisition circuit includes a sampling resistor R3, an operational amplifier U2, a filter capacitor C2, and a second A / D conversion module. The sampling resistor R3 is connected in series in the power supply circuit of the drive motor to acquire the weak voltage signal generated by the motor current. After being amplified by 20 times by the operational amplifier U2, it is input into the A / D conversion module to calculate the actual motor current, which is used for overload and obstacle detection. The relay and MOSFET driving circuit includes a relay, a MOSFET, a driving chip, a freewheeling diode D2, and a protection resistor R3. The driving chip amplifies the control signal from the main control chip, drives the relay to switch the motor power supply circuit on and off, and the MOSFET controls the forward and reverse rotation of the motor. The freewheeling diode D2 absorbs the reverse electromotive force of the motor, and the protection resistor R3 provides overcurrent and overheat protection.

7. A vehicle-mounted control system based on an automatically extending electric step in a motorhome, as described in claim 1, is characterized in that, The anti-pinch and anti-collision protection unit achieves dual obstacle detection through infrared sensors and motor current threshold detection. When an obstacle is detected, the electric step stops moving within 0.1s, and retracts 5cm in the opposite direction after a 2s delay, with the pinching force ≤50N. The specific operating steps are as follows: S101: When the electric stepper body receives the extension / retraction command and the drive motor starts, the anti-pinch and anti-collision protection unit simultaneously completes parameter initialization. When configuring the infrared sensor parameters, the infrared emitting / receiving tube with a wavelength of 940nm is activated, the scanning frequency is set to 100Hz, the detection range covers the 0-30cm area of ​​the stepper extension path, and the preset "no obstacle" light intensity threshold is set - when the light intensity is <500lux, it is judged as an obstruction. At the same time, the current acquisition circuit is activated, the sampling frequency is set to 200Hz, and the "stop response delay ≤0.1s", "reverse retraction delay = 2s", and "reverse retraction distance S = 5cm" are set. At the same time, the fixed parameters of the retraction distance calculation formula are loaded. S102: During the extension and retraction of the electric stepper body, the infrared sensor and current detection work synchronously. When there is no obstacle, the infrared light is unobstructed, the light intensity of the receiver tube is ≥500 lux, and an "no obstacle" signal is output. When there is an obstacle, the infrared light is blocked, the light intensity of the receiver tube is <500 lux, and an "obstacle present" signal is output. The blocking time is recorded. Meanwhile, the current acquisition circuit collects the motor current through sampling resistor R3, and after amplification and filtering, calculates the real-time current value using the second A / D conversion formula. : Where D is the A / D quantization value, and for five consecutive acquisitions By averaging the values ​​and eliminating instantaneous fluctuations, a smoothed current is obtained. : It also calculates the difference between the current smoothing current and the static current to determine whether it is close to the stagnation threshold. ; S103: The controller performs an OR logic judgment on the dual detection results. If the infrared sensor outputs an "obstacle present" signal three times consecutively, and strong light interference is excluded, it is judged as an "infrared anomaly." If the current is ≥15A and the duration is ≥t0, and the clamping force is ≤50N as verified by the clamping force formula, it is determined to be an "abnormal current". The clamping force formula is as follows: If either "infrared anomaly" or "current anomaly" is detected, "obstacle present" is marked, triggering an action response; if both detections are normal, the stepping motion continues. S104: After determining "obstacle present", the controller executes actions in three stages within 0.1 seconds: Level 1: The controller immediately outputs a stop command, the relay disconnects the motor power supply, the MOSFET is cut off, the drive motor stops rotating within 0.1 seconds, and the pedal stops moving; Level 2: Start the "reverse retraction timer", keep the machine in a stopped state for 2 seconds, and the buzzer will sound continuously. During the timer, monitor two signals: if the obstacle is removed, cancel the subsequent retraction action; if it is still abnormal, proceed to the next step. Level 3: Calculate the motor reversal time t using the "retraction distance formula" to ensure a precise retraction of 5cm. The formula used is: ; S105: When the pedal retracts 5cm in the opposite direction, or when the obstacle is removed, the anti-pinch and anti-collision protection unit resets.

8. A vehicle-mounted control system for automatically extending electric steps in a motorhome, as described in claim 1, is characterized in that... The load-bearing detection unit detects the load-bearing status of the electric step body when it starts through the motor current detection circuit. The detection time window is within 0.5 seconds after startup. When the starting current of the drive motor exceeds 8A, it is determined that the load exceeds the allowable range, and the electric step body is controlled to stop immediately and the buzzer alarm is triggered. Its specific operational logic steps are as follows: S201: When the user triggers the electric step extension command and the controller receives the "extension ready" signal, the load detection unit synchronously completes the initialization. S202: When the controller outputs a "motor start command" and the drive motor starts to rotate, the load detection unit immediately enters the "start current detection mode" to continuously collect and process current data. The controller starts the "detection time window timer" to record the motor start time. Ensure that only t∈[ , The current is detected within +0.5s, and automatically exits the load detection mode after 0.5s. The current acquisition circuit acquires the starting current signal in real time through the sampling resistor connected in series in the motor power supply circuit. After amplification and A / D conversion, the real-time motor starting current is calculated using the following formula: Where D is the digital quantization value output by the A / D converter. This is the A / D reference voltage. For A / D resolution, This refers to the operational amplifier's gain. The sampling resistor value was used to collect 100 sets of data within 0.5 seconds. The value is subjected to "peak filtering"—outlier values ​​that are transient disturbances are removed, and the maximum current value is retained. ; S203: When the detection time window ends or a significantly over-threshold current is detected before the end of the detection time window, the controller uses a dual logic of "current threshold judgment + weight formula verification" to determine whether the load exceeds the allowable range: comparing the maximum starting current selected from the data. Overload detection threshold =8A, if ≤8A: Determined as "normal load-bearing capacity", the load-bearing detection unit exits, and the electric stepper continues to extend. >8A: Proceed to the second step, "Weight Formula Verification," to confirm whether it is a genuine overload and calculate the actual load weight G corresponding to the current maximum starting current. Verify whether it exceeds the allowable upper limit of 200kg. The calculation formula is as follows: ; S204: If If the current exceeds 8A and the calculated G is greater than 200kg, it is judged as "load exceeds the allowable range"; if only the current exceeds the threshold but the calculated G is less than or equal to 200kg, it is judged as "current fluctuation", the test result is ignored, and the extension action continues. S205: When the load is determined to be "exceeding the allowable range", the controller will simultaneously execute two operations within 0.1s: immediately stop the electric stepper and sound a buzzer alarm. During the overload alarm, the system locks all extension commands. The lock can only be released after the load is removed by "manually pressing the retraction button" or "unlocking with the remote control" to prevent overload restart.

9. A vehicle-mounted control system for automatically extending electric steps in a motorhome according to claim 1, characterized in that, The MOS transistor drive circuit of the controller's main control board is connected to the drive motor and is used to control the forward and reverse rotation of the drive motor, thereby realizing the extension and retraction of the electric step.

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